Response/Request Size GRPC Metrics Instrumentation

[asweet-confluent]

Adds rpc.request.body.size and rpc.response.body.size attributes. This is just an updated version of #11833.

[asweet-confluent]

Does anyone know why the server spans are using request size for rpc.response.body.size and response size for rpc.request.body.size? This is how the original PR was written.

CC @crossoverJie

[crossoverJie]

Sorry, I'm not really sure about the specific reasons, you can check the commit history of this repo.

However, the previous PR was blocked by this PR, maybe it can be re-pushed.

[jaydeluca]

out of curiosity, are the two of you working together on this? I just want to understand why we have two PRs for the same thing and make sure we're all on the same page. I think the reason the other PR stalled is because there were some open questions about semantic conventions, and as @crossoverJie said we might need to revisit and push on that before we can move forward with this.

[asweet-confluent]

are the two of you working together on this?

No, the other PR is just very out of date I and I wanted to get this done so I rebased it myself. I assumed it was abandoned :)

I think the reason the other PR stalled is because there were some open questions about semantic conventions, and as @crossoverJie said we might need to revisit and push on that before we can move forward with this.

AFAIK these are already in the semantic conventions:

• server
• client

[laurit]

AFAIK these are already in the semantic conventions

What you have in the semantic conventions is rpc.server.request.size, rpc.server.response.size, rpc.client.request.size and rpc.client.response.size metrics. Semantic conventions don't seem to define the span attributes rpc.request.body.size and rpc.response.body.size. Either these attributes would need to be added to semantic conventions or the api that is used to produce the metrics would need to be changed so that it could include values that are not span attributes. Our convention is not to emit telemetry that is not in the spec in default configuration.
To me

                                    equalTo(RPC_RESPONSE_BODY_SIZE, requestSerializedSize),
                                    equalTo(RPC_REQUEST_BODY_SIZE, requestSerializedSize)

looks like a bug since both the request and response size are the same.

[asweet-confluent]

@jaydeluca looks like the failing tests are dead links unrelated to these changes. I'm still unsure of this though.